In a just and sane society, any person calling for the death of his own country's fighting men would be flogged in the city square. His continued presence in the public eye is proof that we do not live in a just or sane society.
As it is, I think that our best option is to utterly ignore him until he goes away.
To pray for the damnation of anyone is a grave sin.
My Jesus, forgive us our sins, save us from the fires of hell, and send all souls into heaven, especially those who have most need of Thy mercy.